An all-age die-off of Rocky Mountain bighorn sheep (Ovis c. canadensis Shaw) occurred from late October 1980 through March 1981 in Waterton Canyon, Colorado, with a loss of 75 to 85% of the sheep. The cause of death was a subacute to chronic bronchopneumonia and the primary etiologic agents isolated from the respiratory system were a Pasteurella sp., P. multocida, Corynebacterium pyogenes, and Protostrongylus stilesi Dikmans, 1931. The underlying predisposing factors that initiated this die-off were believed to be related to multiple chronic environmental stressors associated with the building of a dam which included human contact, vehicular traffic, atmospheric dust, noise and harassment. The die-off was succeeded by a 100% lamb mortality the following summer and a 67% lamb mortality the next two summers. The pneumonia found in these lambs was similar to that found in adult sheep during the previous die-off, except that mature lungworms were absent.
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http://dx.doi.org/10.7589/0090-3558-20.4.319 | DOI Listing |
J Clin Microbiol
January 2025
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA.
We hypothesized that bighorn sheep ewes with chronic nasal carriage are the source of infection that results in fatal lamb pneumonia. We tested this hypothesis in captive bighorn ewes at two study facilities over a 5-year period, by identifying carrier ewes and then comparing lamb fates in groups that did (exposed pens) or did not (non-exposed pens) include one or more carrier ewes. Most (23 of 30) lambs born in exposed pens, but none of 11 lambs born in non-exposed pens, contracted fatal pneumonia.
View Article and Find Full Text PDFMicroorganisms
December 2024
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
Bighorn sheep (BHS) populations have been reported to experience high levels of morbidity and mortality following infection with . This contrasts with the subclinical presentation in domestic sheep (DS). Understanding this difference requires baseline knowledge of pre- and post-infection immune responses of both species.
View Article and Find Full Text PDFSci Rep
December 2024
United States Fish and Wildlife Service, Tulsa, OK, USA.
Abundance estimates inform ungulate management and recovery efforts. Yet effective and affordable estimation techniques remain absent for most ungulates lacking identifiable marks and inhabiting rugged or highly vegetated terrain. Methods using N-mixture models with camera trap imagery form an appealing solution but remain unvalidated.
View Article and Find Full Text PDFAbstractDensity dependence is often assumed in population dynamics, but its importance in small, isolated populations has been questioned. We evaluated the relative influence of density dependence, environmental conditions, and sporadic events (disease outbreaks and specialist predators) on annual population growth rate, annual female reproduction, and annual survival of juveniles and adult females in three populations of mountain ungulates. We analyzed long-term (30-47 years) individual-based data on two bighorn sheep populations and one mountain goat population in Alberta, Canada.
View Article and Find Full Text PDFJ Wildl Dis
November 2024
Southeastern Cooperative Wildlife Disease Study, 589 D. W. Brooks Dr., Athens, Georgia 30602, USA.
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